洞庭湖区湿地演变与地表温度空间格局的关系研究

发布时间：2018-03-04 12:27

  本文选题：洞庭湖区　切入点：湿地　出处：《湖南农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：洞庭湖是我国第二大淡水湖,对区域气候调节和生态环境稳定起着极其关键的作用。然而,受全球变暖及其它因素的影响,洞庭湖湿地面积急剧减少,湿地功能退化严重,生态系统受到严重影响。为了更好地认识洞庭湖区湿地以及地表温度的时空变化特征,弄清洞庭湖对“全球变暖”现象的响应特征、探明湿地变化对地表温度的影响。本文利用1995、2001、2004和2013四年的冬季TM/ETM+遥感影像,采用遥感(RS)、地理信息系统(GIS)、数理统计等方法分析了洞庭湖区的湿地演变特征、地表温度(LST)时空变化特征以及湿地变化对温度的影响。结果表明：(1)洞庭湖区景观类型以水田、旱地、林地为主,水体次之。1995-2013期间,湿地面积逐年减少,尤其是水体面积的减少,由2670.59km2到2078.12km2。各类型之间转化关系复杂,主要表现在水田转化为建设用地和旱地,旱地转化为林地,水体转变为草滩地、芦苇滩地、泥沙滩地。(2)洞庭湖区景观破碎化程度和景观类型形状不规则性不断加大。各景观类型中,水田、建设用地、水体和旱地结构发生明显变化,芦苇滩地、草滩地景观结构较稳定。(3)LST主要以中温区、较高温区和较低温区为主,各等级面积呈正态分布,低温区主要分布在水体,高温区没有明显的空间分布特征。1995-2013年,冬季平均地表温度增加约3.5℃,空间差异性减小。不同区域对全球变暖效应的响应程度表现为东洞庭湖区南洞庭湖区西洞庭湖区。(4)湿地类型平均LST比非湿地类型的低,水体对周围热环境有一定的降温调节作用,当水体面积1 km2时,对周围热环境影响距离约在300m左右。(5)冬季,水汽是影响地表温度最重要的因素。归一化植被指数(NDVI)与地表温度关系不明显；归一化水汽指数(NDMI)与地表温度呈显著负相关关系,尤其在NDMI值为0.2～0.5时；DEM在65米时,与LST呈正相关性,65～365m相关性不明显,365m时呈负相关性,但程度较小。
[Abstract]:Dongting Lake is the second largest freshwater lake in China, which plays a key role in regional climate regulation and ecological environment stability. However, due to global warming and other factors, the wetland area of Dongting Lake has been reduced sharply, and the wetland function has been degraded seriously. The ecosystem is seriously affected. In order to better understand the temporal and spatial variation characteristics of wetland and surface temperature in Dongting Lake region, and to find out the response characteristics of Dongting Lake to the phenomenon of "global warming", The effects of wetland changes on surface temperature were investigated. The characteristics of wetland evolution in Dongting Lake region were analyzed by using TM/ETM remote sensing images in winter of 1995 / 2001 and 2013, using remote sensing, GIS and mathematical statistics, etc. The results showed that the landscape types of Dongting Lake were paddy field, dryland and woodland, and the area of wetland decreased year by year, especially the area of water body, in the period of 1995-2013. From 2670.59 km ~ 2 to 2078.12 km ~ 2. The transformation relationship between different types is complex, mainly manifested in the transformation of paddy field into construction land and dry land, dryland into forest land, water body into grass beach, Reed beach, etc. The degree of landscape fragmentation and the irregularity of landscape type in Dongting Lake region are increasing. Among the landscape types, the structure of paddy field, construction land, water body and dry land are obviously changed. The landscape structure of grass beach is more stable. The main LST is middle temperature area, higher temperature area and lower temperature area, each grade area is normal distribution, low temperature area mainly distributes in water body, and there is no obvious spatial distribution characteristic in high temperature area from 1995 to 2013. The average surface temperature increased about 3.5 鈩，

本文编号：1565651